Impact Guns and Extensions Do Not Mix

I had 3/8 and 1/2 inch beams. I liked the idea of the beams because it seems they can't get out of calibration without looking visually damaged. That lasted till I torqued some head bolts with the engine in the van. Trying to get positioned where the beam could bend to get to the specified toque while being able to see the scale, not cock the handle crooked, while not dragging the pointer in its slot... Then I was lucky to actually be given a good 1/2 clicker. AHHH! Wonderful!!! Enough that I bought a 3/8 clicker for smaller fasteners. Sometimes Old School isn't best.
EDIT: Reading Westend, I don't like to use power tools for final assembly. Like interior trim panels. Fine to use a power driver to dismantle, reluctant to reassemble with it. I think it's too easy to strip the fragile little threads. My worry about tightening wheels with impact is I'll get them over-torqued at home and not be able to loosen them on the road. I use the impact till the nut stops turning then torque wrench (Wonderful CLICKER!!!) to finish up.

CJW8 wrote:
This has been interesting. How would one measure the torque applied by an impact gun? Could you tighten it till it stops turning and then use a torque wrench set on a low setting and keep adjusting the torque wrench up until the bolt moves before it clicks?

You will get in a range of measured torque. If you tighten a bunch of them, you'll get real close, I'll bet.

Instead of running the impact wide open and tightening until it stops, bsck off on the air (assuming this is an air impact). If it's an electric, spin it till the clutch just engages full and then stop. Hopefully both stopping points will be below 110 psi/in torque (or whatever your rim needs). Check with a torque wrench and adjust.

FWIW, I like to use a hand held wrench to finish tightening lug nuts. I'm getting older now so the humanized torque settings start to go down but I get everything tight enough on steel. Aluminum, I usually break out the torque wrench, especially on expensive rims/cars.

smkettner wrote:

CJW8 wrote:
This has been interesting. How would one measure the torque applied by an impact gun? Could you tighten it till it stops turning and then use a torque wrench set on a low setting and keep adjusting the torque wrench up until the bolt moves before it clicks?

Use a beam style over the clicker.

Not according to the training I've had. Clicker beats beam. It's actually hard to get accurate, consistant torques no matter which you use, because it's difficult to judge tightening torque by using loosening torque. And you can't really use where the head clicks or the beam stops as a barometer because you just changed it again by checking it.

We had torque training some years back using the digital calibrator which we calibrate all the torque equipment in the shop with, and beam would get within 15 ft/lb or so, clicker would do around 5. Even with digital processor controlled it is usually off by 2 consistantly. With click and digital, it takes out the human error of judgement and environment influences like angle. Another biggie is whether the fastner is lubed, clean or new/used. Don't forget, we're not really interested in torque per se, other than a measureable parameter of bolt stretch. Stretch is what we're really interested in. Just that it's almost impossible to guage in most cases, so we use torque as a relative measure.

CJW8 wrote:
This has been interesting. How would one measure the torque applied by an impact gun? Could you tighten it till it stops turning and then use a torque wrench set on a low setting and keep adjusting the torque wrench up until the bolt moves before it clicks?

Use a beam style over the clicker.

Go with something like a Thunder Gun or upgrade to a 3/4" drive gun, extension and socket. Glue the parts that attach to the gun with this stuff...

http://www.esabna.com/us/en/products/index.cfm?fuseaction=home.product&productCode=1134


Save your breath about loss of tool heat treatment when welded. I've done this with wrench steel from Indian to Snap-On and still have the often abused modified parts. Allstate 275 is from a different universe. One of the best impossible-fix remedies on the planet.

This has been interesting. How would one measure the torque applied by an impact gun? Could you tighten it till it stops turning and then use a torque wrench set on a low setting and keep adjusting the torque wrench up until the bolt moves before it clicks?

The effect of the impact gun when using an extension is lessened because of the loose tolerances like mentioned, combined with the way the impact gun works.

However, when applying a certain torque value onto a bolt with a torque wrench, the torque value is not changed with the use of an extension on the socket. What would change the torque value is if anything changed the effective leverage of the torque wrench, such as the use of a crow's foot instead of a socket.

They do make`extensions designed to work with impact tools.

Matter of fact, should only used tools specifically designed for impact use in any impact application for a number of reasons.

Really deep (Thor) six point impact sockets are the choice for me. Three quarter inch drive, and a short as possible extension. Big-Rig 1" impact wrenches use a pin and o-ring for retention.

mosseater wrote:
As an aside to the issue at hand, you can gain a tiny mechanical edge with impact extentions if you use your hand to take up the slack in the desired direction of movement. This allows the gun anvil to strike directly on the shaft of the extension by taking out all the slack between socket and nut, and extension and socket. The only remaiing play will be between the anvil and extension, so more efficient use of force from the gun. Grab the extension and turn it in the direction you want to go while hammering with the gun. Not going to solve all your problems but may make the difference between getting it loose and not.

I do not think this is an aside at all, I think it hit the nail on the head. This makes more sense then the extension acting like a torsion bar.

Huntindog wrote:
Nothing is winding up. An impact wrench does just what it's name says. It uses impact as the force. In order for the full force to go into loosening the nut, there needs to be as little play/slop as possible between the wrench and the nut. Every fitting you add, makes the play/slop worse, and the wrench less effective. This is also the reason why impact sockets are always of the 6 point design, To get the tightest possible fit.

ditto, same same but different :)